1. Field of Invention
The present invention relates to a fingerprint recognition system, and more particularly to an optical fingerprint recognition system having a finger board with a plurality of micro-structures.
2. Related Art
U.S. Pat. No. 5,177,802 mainly includes an image capturing element, a light guide plate disposed above the image capturing element, and two light emitting elements disposed at two sides of the light guide plate. When the light emitting elements emit light, the light guide plate guides the incident light to be projected on a finger and then reflected to the image capturing element according to total reflection principle, thus achieving an effect of fingerprint recognition.
However, the light guide plate guides the incident light according to the total reflection principle, and thus during the process of assembling, the incident angle of the light emitting element and the light guide plate must be precisely adjusted, so as to effectively guide the incident light to be projected to parts of the finger. As a result, the assembling is difficult, and the assembling cost is high, and thus the economical effect is poor.